The invention is related to the area of antiviral agents. In particular it is related to the fields of channel-forming toxins and enveloped viruses.
The channel forming toxin aerolysin has been shown to bind GPI-anchored proteins with high affinity (Kd approx. 10xe2x88x929 M for Thy-1; Cowell et al., 1997; Nelson et al., 1997, Diep et al., 1998). The glycosyl portion of the anchor is a binding determinant for the toxin (Diep et al., 1998). Aerolysin is secreted as an inactive 52 kDa precursor called proaerolysin by members of the bacterial genus Aeromonas (see Parker et al., 1996, for a recent review). Binding of aerolysin to GPI-anchored proteins promotes oligomerization of the toxin by concentrating it on the cell surface. As a result, cells displaying GPI-anchored proteins are far more sensitive to the toxin than those that do not (Nelson et al., 1998; Brodsky et al., 1999). The heptameric oligomers that are formed following binding are able to insert into the membrane, forming stable 1 nm channels that destroy the permeability barrier and cause cell death.
Human immunodeficiency virus (HIV) is the pathogenic agent that causes acquired immunodeficiency syndrome (AIDS). Efforts to cure HIV have yielded temporary and incomplete effects. There is a continuing need in the art for new therapeutic methods for treating human viruses, particularly those such as HIV which cause chronic infections.
It is an object of the invention to provide a method of treating a population of enveloped viruses which comprise a glycosylphosphatidylinositol-anchored protein in their membrane.
It is another object of the invention to provide an attenuated viral vaccine.
It is a further object of the invention to provide a method of purging a blood product, cell suspension, or tissue of enveloped viruses which comprise a glycosylphosphatidylinositol-anchored protein in their membrane.
It is yet another object of the invention to provide a method of detecting the presence of an enveloped virus in a sample.
These and other objects of the invention are provided by one or more of the embodiments below.
In one embodiment of the invention, a method is provided for treating a population of enveloped viruses which comprise a glycosylphosphatidylinositol-anchored protein in their membrane. The method comprises the step of contacting the population of enveloped viruses with a toxin which binds to glycosylphosphatidylinositol-anchors. The toxin is present in an amount sufficient to reduce infectivity of the population of viruses by at least 50%.
In another embodiment of the invention, an attenuated viral vaccine is provided. The vaccine comprises a population of enveloped virus particles which comprise a glycosylphosphatidylinositol-anchored protein in their membranes. The vaccine further comprises an oligomerized toxin bound to the glycosylphosphatidylinositol-anchored protein. The oligomerized toxin forms a channel. The infectivity of the population of enveloped virus particles is reduced by at least 50% compared to a population of the enveloped virus particles without the oligomerized toxin.
In another embodiment of the invention, a method is provided for purging a blood product, cell suspension, or tissue of enveloped viruses which comprise a glycosylphosphatidylinositol-anchored protein in their membrane. The method comprises the step of contacting the blood product, cell suspension, or tissue with a toxin which binds to glycosylphosphatidylinositol-anchors. The amount of the toxin is sufficient for the toxin to bind to at least 50% of the virus present in the blood product, cell suspension, or tissue.
In a further embodiment of the invention, a method is provided for detecting the presence of an enveloped virus in a sample. The method comprises the steps of contacting a cell-free extract of a sample with a a toxin which binds to glycosylphosphatidylinositol-anchors, allowing enveloped virus in the sample to bind to the toxin, and detecting the toxin which bound to the virus. The presence of toxin bound to virus indicates enveloped virus in the sample.
These and other objects of the invention provide the art with new methods and reagents for detecting, treating, and preventing the spread of enveloped viruses.